How to identify the DHCP-assigned IP address of a routed client?

[neilbalch]

I'm trying to ssh into another device I connected to the Raspberry Pi running your wifi-to-eth-route.sh script. However, I can't seem to figure out how to identify what IP address it was given.

I tried looking in the journalctl output for the systemd service I setup to run your script on startup, but there seems to be no relevant output. Could you shed some light on this issue? Thanks!

[arpitjindal97]

I think dnsmasq stores it somewhere in the file. See this

[neilbalch]

Oh and I also just realized I'm having issues with the client not receiving internet access when using the script... :)

[arpitjindal97]

Try to install all the packages mentioned in the top section of script.

[neilbalch]

Try to install all the packages mentioned in the top section of script.

All of the commands are run without error, so I don't think that's the issue.

[myxxmikeyxx]

After running all the commands individually did it work for getting internet access?
We had the issue where we needed bring the interfaces down then up to apply our changes but I know I had the issue where the script was running too soon so I needed to wait for everything to finish then have the script run so under #! bin/bash/ I put sleep 120 so it waited 2 minutes to start up. Also so something about maybe putting it in crontab -e doing something like @reboot sleep 10 && sudo bash /home/pi/wifi-to-eth-route.sh

[neilbalch]

After running all the commands individually did it work for getting internet access?
We had the issue where we needed bring the interfaces down then up to apply our changes but I know I had the issue where the script was running too soon so I needed to wait for everything to finish then have the script run so under #! bin/bash/ I put sleep 120 so it waited 2 minutes to start up. Also so something about maybe putting it in crontab -e doing something like @reboot sleep 10 && sudo bash /home/pi/wifi-to-eth-route.sh

Interesting. Admittedly, I'm not very skilled or experienced with using Linux network interface configuration tools, so I don't know what useful information I can provide here to help resolve the issue.

As for the premature run, I don't think this is the problem. The script doesn't work (i.e. provide bridged internet access on the LAN port) if I run it manually after logging in via ssh after boot.

[myxxmikeyxx]

Is it possible to start form a fresh Raspbian install?
I just did a fresh install tonight and then connect to my Wi-Fi.
I enabled ssh and then used putty on my desktop
then did sudo apt-get update && sudo apt-get upgrade -y
let that finish then I did sudo apt-get install dnsmasq -y
next I did cd /home/pi && wget https://raw.githubusercontent.com/arpitjindal97/raspbian-recipes/master/wifi-to-eth-route.sh
after that I added it to sudo nano /etc/xdg/lxsession/LXDE-pi/autostart
I added sudo bash /home/pi/wifi-to-eth-route.sh
saved it and did a reboot
after reboot I checked by doing ifconfig and eth should have an IP of 192.168.2.1

[neilbalch]

Okay, interesting! I probably won't have time to try this until next weekend though.

[myxxmikeyxx]

@neilbalch Are you still able to test it this weekend?

[neilbalch]

@neilbalch Are you still able to test it this weekend?

Oh crap, lol... I forgot last weekend. I'll do my best to try this Saturday...

[neilbalch]

Sorry guys, I've been very busy with school lately... I'll get to it soon. 😦

[myxxmikeyxx]

@neilbalch not a problem. I am in college and have been super busy with class projects and finals around the corner so I understand the feeling well.

[neilbalch]

Ah! Progress? I get this issue when running the script on a fresh and fully updated RPi: (https://superuser.com/q/1480986/342885)

pi@RPi3Bplus:~ $ bash wifi-to-eth-route.sh
iptables/1.8.2 Failed to initialize nft: Protocol not supported
iptables/1.8.2 Failed to initialize nft: Protocol not supported
iptables/1.8.2 Failed to initialize nft: Protocol not supported
iptables/1.8.2 Failed to initialize nft: Protocol not supported
iptables/1.8.2 Failed to initialize nft: Protocol not supported
pi@RPi3Bplus:~ $

Seems to be related to a change in iptables' API or being depricated in the future? And a direct search and replace adding -legacy to every iptables command doesn't work either for me:

pi@RPi3Bplus:~ $ bash wifi-to-eth-route.sh
iptables v1.8.2 (legacy): can't initialize iptables table `filter': Table does not exist (do you need to insmod?)
Perhaps iptables or your kernel needs to be upgraded.
iptables v1.8.2 (legacy): can't initialize iptables table `nat': Table does not exist (do you need to insmod?)
Perhaps iptables or your kernel needs to be upgraded.
iptables v1.8.2 (legacy): can't initialize iptables table `nat': Table does not exist (do you need to insmod?)
Perhaps iptables or your kernel needs to be upgraded.
iptables v1.8.2 (legacy): Couldn't load match `state':No such file or directory

Try `iptables -h' or 'iptables --help' for more information.
iptables v1.8.2 (legacy): can't initialize iptables table `filter': Table does not exist (do you need to insmod?)
Perhaps iptables or your kernel needs to be upgraded.
pi@RPi3Bplus:~ $

[myxxmikeyxx]

Did you make sure to do:
sudo apt-get update sudo apt-get upgrade -y

Did you also install the required packages:
sudo apt-get install dnsmasq -y

Also can you run this and screen shot or copy the output:
cat /etc/os-release

And lastly can you do:
iptables --version

[neilbalch]

Did you make sure to do:
sudo apt-get update sudo apt-get upgrade -y

Did you also install the required packages:
sudo apt-get install dnsmasq -y

Yes to both. :) I followed your steps exactly, but I never added the command to any autorun script. I just ran it manually from the bash prompt.

Also can you run this and screen shot or copy the output:
cat /etc/os-release

And lastly can you do:
iptables --version

pi@RPi3Bplus:~ $ cat /etc/os-release
PRETTY_NAME="Raspbian GNU/Linux 10 (buster)"
NAME="Raspbian GNU/Linux"
VERSION_ID="10"
VERSION="10 (buster)"
VERSION_CODENAME=buster
ID=raspbian
ID_LIKE=debian
HOME_URL="http://www.raspbian.org/"
SUPPORT_URL="http://www.raspbian.org/RaspbianForums"
BUG_REPORT_URL="http://www.raspbian.org/RaspbianBugs"
pi@RPi3Bplus:~ $ iptables --version
iptables v1.8.2 (nf_tables)
pi@RPi3Bplus:~ $